Question

Ralph is 3 times as old as Sara. In 4 years, Ralph will be only twice as old as Sara will be then. Find Ralph's age now. If x represents Sarah's age now, which of the following expressions represents Ralph's age in four years?

3x
6x
2x + 4
3x + 4

Answer 1

2x + 4

Explanation:

Let R = Ralph's age

and x = Sarah's age

Then Ralph's age in 4 years = R + 4

and Sarah's age in four years = x + 4

Thus, R + 4 = 2(x + 4)

Distribute the 2 R + 4 = 2x + 8

Subtract 4 from each side R = 2x + 4

Ralph's age is 2x + 4.